1 /* 2 * Copyright (c) 2015-2020 François Tigeot <ftigeot@wolfpond.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #ifndef _LINUX_PAGEMAP_H_ 28 #define _LINUX_PAGEMAP_H_ 29 30 #include <linux/mm.h> 31 #include <linux/fs.h> 32 #include <linux/list.h> 33 #include <linux/highmem.h> 34 #include <linux/compiler.h> 35 #include <asm/uaccess.h> 36 #include <linux/gfp.h> 37 #include <linux/bitops.h> 38 #include <linux/hardirq.h> 39 40 static inline int 41 fault_in_pages_writeable(char __user *uaddr, int size) 42 { 43 int ret = 0; 44 char __user *end = uaddr + size - 1; 45 46 if (unlikely(size == 0)) 47 return ret; 48 49 /* 50 * Writing zeroes into userspace here is OK, because we know that if 51 * the zero gets there, we'll be overwriting it. 52 */ 53 while (uaddr <= end) { 54 ret = subyte(uaddr, 0); 55 if (ret != 0) 56 return -EFAULT; 57 uaddr += PAGE_SIZE; 58 } 59 60 /* Check whether the range spilled into the next page. */ 61 if (((unsigned long)uaddr & ~PAGE_MASK) == 62 ((unsigned long)end & ~PAGE_MASK)) 63 ret = subyte(end, 0); 64 65 return ret; 66 } 67 68 static inline int 69 fault_in_pages_readable(const char __user *uaddr, int size) 70 { 71 char c; 72 int ret = 0; 73 const char __user *end = uaddr + size - 1; 74 75 if (unlikely(size == 0)) 76 return ret; 77 78 while (uaddr <= end) { 79 ret = -copyin(uaddr, &c, 1); 80 if (ret != 0) 81 return -EFAULT; 82 uaddr += PAGE_SIZE; 83 } 84 85 /* Check whether the range spilled into the next page. */ 86 if (((unsigned long)uaddr & ~PAGE_MASK) == 87 ((unsigned long)end & ~PAGE_MASK)) { 88 ret = -copyin(end, &c, 1); 89 } 90 91 return ret; 92 } 93 94 static inline gfp_t 95 mapping_gfp_mask(struct vm_object * mapping) 96 { 97 /* XXX Linux mappings have an associated gfp_mask attribute */ 98 return GFP_KERNEL; 99 } 100 101 static inline gfp_t 102 mapping_gfp_constraint(struct vm_object *mapping, gfp_t gfp_mask) 103 { 104 return (mapping_gfp_mask(mapping) & gfp_mask); 105 } 106 107 #endif /* _LINUX_PAGEMAP_H_ */ 108